.TH deductionguidesforstd::basic_string_view 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
deductionguidesforstd::basic_string_view \- deductionguidesforstd::basic_string_view

.SH Synopsis
   Defined in header <string_view>
   template< class It, class End >
   basic_string_view( It, End ) ->                                    \fB(1)\fP \fI(since C++20)\fP
   basic_string_view<std::iter_value_t<It>>;
   template< class R >
   basic_string_view( R&& ) ->                                        \fB(2)\fP (since C++23)
   basic_string_view<ranges::range_value_t<R>>;

   These deduction guides are provided for std::basic_string_view.

   1) This deduction guide allow the character type to be deduced from the
   iterator-sentinel pair. This overload participates in overload resolution only if It
   satisfies contiguous_iterator and End satisfies sized_sentinel_for for It.
   2) This deduction guide allow the character type to be deduced from the range. This
   overload participates in overload resolution only if R satisfies contiguous_range.

.SH Example


// Run this code

 #include <array>
 #include <iostream>
 #include <string_view>

 int main()
 {
     std::array a1{'n', 'u', 'c', 'l', 'e', 'o', 'n', 's', ':', '\\n'};
     std::basic_string_view s1(a1.cbegin(), a1.cend()); // deduction: CharT -> char
     static_assert(std::is_same_v<decltype(s1)::value_type, char>);
     std::cout << s1;

     std::array a2{L'p', L'r', L'o', L't', L'o', L'n', L's', L'\\n'};
     std::basic_string_view s2(a2.cbegin(), a2.cend()); // deduction: CharT -> wchar_t
     static_assert(std::is_same_v<decltype(s2)::value_type, wchar_t>);
     std::wcout << s2;

     std::array<long, 9> a3{'n', 'e', 'u', 't', 'r', 'o', 'n', 's', '\\n'};
     std::basic_string_view s3(a3.cbegin(), a3.cend()); // deduction: CharT -> long
     static_assert(std::is_same_v<decltype(s3)::value_type, long>);
     for (const auto e : s3)
         std::cout << static_cast<char>(e);
 }

.SH Output:

 nucleons:
 protons
 neutrons
